ch 22 Flashcards
conduction - Send A Big Bounding Pulse
- SA node
- AV Node
- Bundle of His
- R/L Bundle Branches (right and left)
- Purkinje Fibers
depolarization: - to + contraction
Re-polarization + to - relaxation
cardiac conduction system generates and transmits electrical impulses which stimulates contraction of the atria and then the ventricles
SA Node (SinoAtrial node)
“automaticity”
primary pace maker of the heart
creates electrical impulse of 60-100 BPM (normal heart rate)
AV Node (AtrioVentricular)
secondary pacemaker of the heart (backup pacemaker)
if SA node malfunctions, the AV node takes over
40-60 BPM
purkinje fibers
if SA and AV nodes fail the purkinje fibers can fire at a rate of 30-40 BPM
P Wave
reflects conduction of an electrical impulse through the atrium
represent atrial depolarization
QRS Complex
reflects conduction of an electrical impulse through the ventricles
represent the ventricles depolarization
T Wave
reflects repolarization of the ventricles
PR Segment
flat line between the end of P-wave and the start of QRS Complex
reflects the delay between atrial and ventricular activation
ST Segment
reflects the end of QRS Complex to the beginning of the T wave
PR Interval
reflects the conduction of an electrical impulse from the sinoatrial node (SA) through the atrioventricular node (AV)
QT interval
reflects the time from ventricular depolarization through repolarization
measured from beginning of QRS complex to the end of the T wave
RR Interval
the duration between the beginning of one QRS complex and the beginning of the next QRS complex
used to calculate ventricular rate and rhythm
PP Interval
the duration between the beginning of one P wave and the beginning of the next P wave
used to calculate atrial rate and rhythm
U Wave
reflect the purkinje fibers repolarization
not seen unless patient is hypokalemic (low Potassium)
Basic rhythms
normal sinus: 60-100 bpm
sinus tachycardia: > 100 bpm
sinus bradycardia: < 60 bpm
ekg interpretation: P wave
should be present and upright
comes before QRS complex
one P-wave for every QRS Complex
EKG interpretation: PR Interval
measure PR interval
normal: 0.12 - 0.2 seconds
EKG Interpretation: QRS Complex
is every P wave followed by a QRS complex?
should not be widened or shortened - may indicate problems
widened is often seen in PVCs, electrolyte imbalances, and drug toxicity
normal: 0.06 - 0.12 seconds